Permanent dental prosthesis and method

ABSTRACT

A base structure for a dental prosthesis comprises first and second anchor elements which are permanently securable to the teeth on opposite sides of a space or gap in the tooth structure of a patient and a base element which is securable to the anchor elements in the gap but which comprises slidably interfitted first and second base element portions so that it is expendable to fit the width of the gap. The method of securing and forming a dental prosthesis in the gap with the base structure comprises the steps of securing the anchor elements on the teeth on opposite sides of the gap, assembling the base element with the anchor elements in the gap, securing the first and second base element portions together, forming an outer shell on the base element and securing the base element with the outer shell thereon to the anchor elements.

BACKGROUND AND SUMMARY OF THE INVENTION

The instant invention relates to the field of dentistry, and moreparticularly to an improved base structure for a dental prosthesis andto a method of installing and assembling the prosthesis in the mouth ofa patient.

A variety of different types of removable and permanent dentalprostheses have been heretofore available for replacing missing teeth inthe mouths of patients. In this connection, conventional removabledental bridges possibly represent the most common type of heretoforeavailable dental prosthesis, and they have been utilized for replacingmissing teeth in mouths of patients for many years. Other types ofheretofore-available removable dental prostheses are disclosed in theU.S. Pat. Nos. 1,685,289 to Miller; 1,702,282 Stoloff; 3,717,931 Konig;4,302,187 Yoon; 4,345,901 Romagnoli; 4,348,181 Dawson; 4,380,434Weissman; and 4,406,622 Yoon. More recently, however, it has beenrecognized that it is possible to permanently secure a dental prosthesisin the mouth of a patient to provide a permanent replacement for one ormore missing teeth and that a permanent prosthesis can have significantadvantages over a removable prosthesis from a practical standpoint. Thedevice disclosed in the U.S. Pat. No. 4,163,318 to Tigani whichrepresents the closest prior art to the instant invention of which theapplicants are aware and the device disclosed in the applicants'copending U.S. pat. application Ser. No. 751,371 now U.S. Pat. No.4,609,355 issued on 9/02/86 are generally exemplary of some of the typesof permanent dental prostheses which have been heretofore known.Generally, the heretofore known permanent dental prostheses havecomprised a body portion which defines an artificial tooth or at least abase structure for an artificial tooth and a pair of pins or tabs whichextend outwardly from opposite sides of the body portion and arereceivable in notches or holes in the adjacent natural teeth forsecuring the body portion between the two natural teeth. In most cases,the pins or tabs of a prostheses of this type have beem cemented in theholes or notches in the adjacent teeth to secure the body portion of theprosthesis in position. As an alternative to this type of structure,another type of permanent dental prosthesis has recently been developedcomprising anchor elements which are permanently securable to the sidesof the teeth on either side of an opening or gap in the mount of apatient and a body portion which is permanently securable to the anchorelements to secure it in the gap. In this connection, the anchorelements which are used in a prosthesis of this type are permanentlysecurable to the adjacent teeth with pins which are cemented in smallholes in the adjacent teeth, Until recently, it was not practical tosecure anchor elements in this manner since it was extremely difficultto drill the proper holes with the types of dental drills which areavailable. However, recent improvements in dental drills have now madethe use of anchor elements of this type practical. In any event, it hasbeen found that anchor elements which are permanently secured to teethin this manner can provide an effective and durable means of securing adental prosthesis in the mouth of a patient. Nevertheless, althoughanchor elements of this type have recently been used for securingartificial teeth in the mouths of patients, they have only been used incombination with preformed artificial teeth which have not beenadjustable to fit gaps of different sizes and which have thereforerequired substantial mounts of custom dental work in order to adapt andfit them to the mouths of patients and in order to adapt them to besecured with anchor elements.

The instant invention provides a novel and effective base structure fora dental prosthesis which is securable in the mouth of a patient withanchor elements of the above-described type but which is adjustable toadapt it to be installed in the mouth of a patient without substantialamounts of custom dental laboratory work. Specifically, the basestructure for a dental prosthesis of the instant invention comprisesfirst and second anchor elements which are securable on the sides ofspaced first and second teeth and a base element which is securable tothe anchor elements to retain the base element in the gap between thefirst and second teeth. The base element, however, comprises first andsecond base element portions which are received in interfitting relationand slidable in telescoping relation with respect to each other in adirection which extends between the anchor elements to enable the baseelement to be adjusted to fit the width of the gap. The anchor elementsare preferably tapered in their outward extents away from the gum of thepatient when they are mounted on their respective teeth, and the baseelement is configured to receive the first and second anchor elements insnug, interfitting relation when the base element is aligned with thegap and advanced toward the gum. The first and second base elementportions preferably define a tooth-like configuration of slightlyreduced dimension in the base element, the first base element portionpreferably has an aperture therein which is disposed in a directionwhich extends between the anchor elements, and the second base elementportion preferably comprises a pin which is slidably received in theaperture in the first base element portion to enable the first andsecond base element portions to be slidably adjusted in telescopingrelation with respect to each other. Further, the pin in the second baseelement portion is preferably received in the aperture in the first baseelement portion so that the first and second base element portions areslightly rotatable with respect to each other to compensate for minormisalignments in the positions of the anchor elements on the adjacentteeth and in one embodiment of the base structure, a spring is providedfor biasing the first and second base element portions apart.

In order to secure and form a dental prosthesis in the mouth of apatient in accordance with the method of the instant invention, firstand second anchor elements are secured to spaced first and second teeth,respectively, on opposite sides of a gap in the mouth of a patient, andthe base element is assembled in the gap so that it is received ininterfitting relation with the anchor elements. In this regard, becausethe first and second base element portions are slidable with respect toeach other and preferably slightly rotatable, they can easily beinterfitted and assembled with the anchor elements without requiringcustom dental laboratory work. After the base element has been assembledwith the anchor elements in the gap in this manner, the first and secondbase element portions are permanently secured with respect to eachother, and an outer shell or casing having a tooth-like outerconfiguration is formed over the base element. Thereafter, the baseelement with the outer casing thereon is secured to the anchor elementsto provide a permanently secured prosthesis in the mouth of the patient.In the preferred application of the method, after the anchor elementshave been secured on the first and second teeth in the mouth of thepatient but before the base element has been assembled in the gap, astudy model is made of the first and second teeth with the anchorelements thereon by conventional dental techniques. The base element isthen assembled with the anchor elements in the gap and the first andsecond base element portions are cemented together. Thereafter, the baseelement is removed from the patient's mouth and placed on the studymodel, the outer shell is formed on the base element while it is on thestudy model, and finally the base element with the outer shell thereonis installed in the mouth of the patient and secured to the anchorelements with a suitable cement.

Accordingly, it is a primary object of the instant invention to providean effective base structure for a permanent dental prosthesis.

Another object of the instant invention is to provide a dentalprosthesis comprising an adjustable base element and a pair of anchorelements which are securable to a pair of spaced teeth in the mouth of apatient.

A still further object of the instant invention is to provide animproved method of forming and securing one or more artificial teeth inthe mouth of a patient.

Other objects, features and advantages of the invention shall becomeapparent as the description thereof proceeds when considered inconnection with the accompanying illustrative drawings.

DESCRIPTION OF THE DRAWINGS

In the drawings which illustrate the best mode presently contemplatedfor carrying out the present invention:

FIG. 1 is an enlarged exploded perspective view of the base structure ofthe instant invention;

FIG. 2 is an enlarged exploded perspective view of the base element of asecond embodiment of the base structure;

FIG. 3 is an enlarged fragmentary elevational view of the jaw and toothstructure of a patient with a pair of anchor elements assembled on apair of the teeth thereof;

FIG. 4 is a similar view with the base element assembled with the anchorelements;

FIG. 5 is a similar view with the first and second portions of the baseelement secured together; and

FIG. 6 is a similar view with the outer casing assembled on the basestructure.

DESCRIPTION OF THE INVENTION

Referring now to the drawings, a first embodiment of the base structureof the instant invention is illustrated in FIGS. 1, 4 and 5 andgenerally indicated at 10. The base structure 10 comprises a baseelement generally indicated at 12 and first and second anchor elementsgenerally indicated at 14 and 16, respectively, in FIGS. 1 and 3 whichare receivable in assembled relation with the base element 12 forsecuring it in the mouth of a patient. More specifically, the anchorelements 14 and 16 are securable on first and second teeth 18 and 20which define a gap 22 therebetween and which are mounted on a gumstructure 23 comprising a gum 24. When the anchor elements 14 and 16 aremounted in this manner, the base element 12 is receivable in the gap 22for providing a rugged and durable base structure for a permanent dentalprosthesis comprising one or more artificial teeth. A base element of asecond embodiment of the base structure of the instant invention isillustrated and generally indicated at 25 in FIG. 2, and it is adaptedto be mounted in a similar manner on similar anchor elements in asimilar gap.

The anchor elements 14 and 16 are preferably of conventionalconstruction and preferably made of a suitable corrosion-resistant metalwhich is suitable for dental applications, such as stainless steel, andthe anchor elements 14 and 16 each comprises a body portion 26 and apair of spaced pins 28. The body portions 26 are each preferably formedin a generally truncated conical configuration, although they havelongitudinally extending flattened sides 30 thereon which are receivablein substantially mating relation with the sides of the teeth 18 or 20 toenable them to be effectively mounted thereon. In addition, the surfacesof the body portions 26 are preferably etched by conventional techniquesto make them more receptive to adhesives. The pins 28 are assembled withthe body portions 26 so that they project from the flattened sides 30thereof, and they are preferably formed with spaced annular rings 31thereon which enable them to be more effectively cemented in holes inthe sides of the teeth 18 and 20. It will be understood, however, thatwhile the anchor elements 14 and 16 are herein embodied as havinggenerally truncated conically shaped body portions 26 and as each havingtwo spaced pins 28, it will be understood that the base structures 10can be effectively constructed with other types of anchor elementshaving body portions of different configurations and having differentquantities of pins 28.

The base element 12 is preferably made of a suitable corrosion-resistantmetal which is suitable for dental applications, such as stainlesssteel, and it comprises first and second base element portions generallyindicated at 32 and 34, respectively, which preferably cooperate todefine a reduced tooth-like configuration in the base element 12 andwhich are preferably etched on the surfaces thereof to make them morereceptive to adhesives, composite filler materials, etc. The baseelement portions 32 and 34 have inner mating surfaces 36 and 38,respectively, which are receivable in substantially mating relation, abore 40 is formed and positioned in the first base element portion 32 sothat it extends inwardly from the inner mating surface 36 thereon, and apin 42 is formed and positioned in the second base element portion 34 sothat it projects outwardly from the inner mating surface 38 thereon. Thebore 40 and the pin 42 are positioned on their respective base elementportions 32 and 34 so that the pin 42 is slidably receivable in the bore40 and so that the bore 40 and the pin 42 cooperate for retaining thefirst and second base element portions 32 and 34, respectively, ingenerally aligned relation. Accordingly, when the pin 42 is entirelyreceived in the bore 40, the mating surfaces 36, 38 are preferablyreceived in mating engagement, although the first and second baseelement portions 32 and 34, respectively, are preferably at leastslightly rotatable with respect to each other to compensate for slightmisalignments in the positions of the anchor elements 14 and 16. Formedon the sides of the first and second base element portions 32 and 34which face generally away or opposite from the mating surfaces 36 and 38thereof, respectively, are first and second notches 44 and 46,respectively, which are dimensioned and configured to receive the firstand second anchor elements 14 and 16, respectively. More specifically,the notches 44 and 46 are preferably formed in generally open-sidedtruncated conical configurations, and they are oriented to receive theanchor elements 14 and 16, respectively, when the base element 10 isgenerally aligned with the gap 22 and advanced therein toward the gum24. Further, since the pin 42 is slidable in telescoping relation in thebore 40, the width of the base element 12 is automatically adjusted tofit the width of the gap 22 when the base element 12 is assembled withthe anchor elements 14 and 16 in this manner.

The base element 25 is similar to the base element 12, it is made of asuitable metal, and it includes first and second base element portions48 and 50, respectively, which are preferably etched on the surfacesthereof, and a resilient spring 52. The base element portions 48 and 50have mating surfaces 54 and 56 thereon, respectively, and a bore 58extends inwardly from the mating surface 54 on the first base elementportion 48, whereas a pin 60 projects outwardly from the mating surface56 on the second base element portion 50. The bore 58 extends partiallythrough the first base element portion 48, the spring 52 is received inthe bore 58, and the pin 60 is slidably received in the bore 58, so thatthe spring element 52 biases the first and second base element portions48 and 50 apart. Formed on the outer sides of the first and second baseelement portions 48 and 50 which face generally opposite or away fromthe mating surfaces 54 and 56 thereof are notches 62 and 64 which aredimensioned and configured to receive the anchor elements 14 and 16,respectively, in interfitting assembled relation for securing the baseelement 25 in the gap 22.

The method of the instant invention can be effectively applied to formand assemble a permanent dental prosthesis in the mouth of a patientwhich includes a base element such as the base element 10 or the baseelement 25. In this regard, the method of the instant invention isherein described as it is applied with the base element 12, although itwill be understood that the base element 25 could also be installed inaccordance with the method to form an effective dental prosthesis. Inthe first step of the method of the instant invention as hereinembodied, the anchor elements 14 and 16 are permanently installed on theteeth 18 and 20 in the gap 22. The anchor elements 14 and 16 arepreferably installed in a conventional manner by first drilling smallholes in the sides of the teeth 18 and 20 which face the gap 22 and bythen cementing the anchor elements 14 ad 16 to the teeth 18 and 20,respectively, so that the pins 28 on the anchor elements 14 and 16extend into the drill holes in the teeth 18 and 20. In this regard, theportions of the teeth 18 and 20. In this regard, the portions of theteeth 18 and 20 which face the surfaces 30 on the anchor elements 14 and16 are preferably etched before the anchor elements 14 and 16 arecemented to the teeth 18 and 20 to provide effective bonding surfacesfor the anchor elements 14 and 16, and thereafter the anchor elements 14and 16 are preferably cemented to the teeth 18 and 20 with an effectiveand durable dental cement, such as a glass cement ionomer or a resincement. After the anchor elements 14 and 16 have been permanentlysecured to the teeth 18 and 20 in this manner, a study model of theteeth 18 and 20 with the anchor elements 14 and 16 thereon is preferablymade in a conventional manner so that a portion of the remainder of themethod can be effected outside of the mouth of the patient. In anyevent, after the anchor elements 14 and 16 have been assembled on theteeth 18 and 20, respectively, the base element 12 is assembled with theanchor elements 14 and 16 in the gap 22. This is carried out bypositioning the base element 12 so that it is aligned with the gap 22and so that the first and second notches 44 and 46 are aligned with thefirst and second anchor elements 14 and 16, respectively, and bythereafter advancing the base element 12 toward the gum 24 in the gap 22so that it is positioned in the manner illustrated in FIG. 4. In thisregard, since the pin 42 is slidable in telescoping relation in the bore40, the width of the base element 12 is automatically adjusted to fitthe width of the gap 22 by aligning the notches 44 and 46 with theanchor elements 14 and 16, respectively. Further, because of the roundedconfigurations of the anchor elements 14 and 16 and the notches 44 and46, and because the base element portions 32 and 34 are slidablyinterfitted and at least slightly rotatable with respect to each other,the base element 12 can effectively compensate for minor misalignmentsbetween the teeth 18 and 20, as well as minor misalignments in thepositions of the anchor elements 14 and 16 thereon. After the baseelement 12 has been assembled in the gap 22 in this manner, a cement 66is applied to the base element portions 32 and 34, as illustrated inFIG. 5, in order to secure them with respect to each other. This ispreferably carried out by utilizing a conventional dental cement or acomposite material such as a ceramic composite material, and the entirespace between the base element portions 32 and 34 is preferably filledwith the cement or composite material to provide a solid structure.Finally, after the cement or composite material 66 has been applied tothe base element portions 32 and 34 to permanently secure them together,an outer shell 68 is formed in a tooth-like configuration over the baseelement 12. This is preferably carried out by first removing the baseelement 12 from the mouth of the patient and assembling it on the studymodel and by thereafter applying a ceramic composite material or aceramic composite material plus a porcelain or acrylic veneer over thebase element 12 to provide a tooth-like outer configuration thereforwhich is customized for the patient to provide an effective artificialtooth, such as the one generally indicated at 70 in FIG. 6. Finally,after the tooth 70 has been fully formed in this manner, it is cementedto the anchor elements 14 and 16 with a permanent cement, such as aglass ionomer cement or a resin cement so that it is permanently securedin the gap 22 in the position illustrated in FIG. 6.

It is seen, therefore, that the instant invention provides an effectivebase structure for a dental prosthesis and an effective method ofassembling and forming a dental prosthesis in the mouth of a patient.The base elements 12 and 25 can be effectively adjusted to fit thewidths of gaps in the mouths of patients, and the base elements 12 and25 can be effectively utilized in the method of the instant inventionfor forming effective dental prostheses, such as the finished tooth 70.Further, the base elements 12 and 25 can be effectively and permanentlysupported on the anchor elements 14 and 16 to provide base structuresfor artificial teeth which are durable and which can be adapted toprovide aesthetically pleasing replacement teeth in the mouths ofpatients. In addition, since the base element of the base structure isadjustable to fit the width of a gap in the mouth of a patient and alsoto compensate for minor misalignments in the adjacent teeth and thepositions of the anchor elements, the entire method can normally beperformed in a dentist's office without requiring custom dental labwork. Accordingly, it is seen that the base structure of the instantinvention and the method of forming an artificial tooth in accordancewith the instant invention represent significant advancements in thedental art which have substantial commercial merit.

While there is shown and described herein certain specific structureembodying the invention, it will be manifest to those skilled in the artthat various modifications and rearrangements of the parts may be madewithout departing from the spirit and scope of the underlying inventiveconcept and that the same is not limited to the particular forms hereinshown and described except insofar as indicated by the scope of theappended claims.

What is claimed is:
 1. In a base structure for a dental prosthesiswherein the base structure is of the type whichis permanently securablein a gap between spaced first and second teeth in the mouth of a patientand comprises first and second anchor elements securable on said firstand second teeth, respectively, in said gap and a base element securableto said first and second anchor elements when they are secured on theirrespective teeth to retain said base element in a position wherein itextends therebetween, the improvement comprising said base elementcomprising first and second base element portions which are receivablein interfitting relation with said first and second anchor elements,respectively, so that they are nonrotatable relative to said anchorelements, respectively, about an axis which extends in a directionbetween said first and second anchor elements and permanently securableto said first and said anchor elements, respectively, and which arereceived in interfitting relation and rotatable with respect to eachother and slidble in telescoping relation with respect to each other insaid direction to enable said base element to be adjusted to fit thewidth of said gap and to compensate for misalignment of said anchorelements.
 2. The base structure of claim 1 further comprising meansbiasing said base element portions apart.
 3. In the base structure ofclaim 1, said anchor elements further characterized as being tapered intheir outward extents away from the gum of said patient when they aremounted on said first and second teeth, said first and second baseelement portions being configured to receive said first and secondanchor elements, respectively, in snug interfitting relation when saidbase element is aligned with said gap and advanced toward said gum. 4.In the base structure of claim 1 said first base element portion havingan aperture therein which extends in said direction between said anchorelements, said second base element portion comprising a pin which isslidably received in said aperture to enable said base element to beadjusted.
 5. The base structure of claim 4 further comprising springmeans received in said aperture and engaging said pin to bias said firstand second base element portions apart.
 6. In the base structure ofclaim 1 said first and second base element portions defining atooth-like configuration of reduced dimension in said base element. 7.The base structure of claim 1 in combination with an outer shell, saidbase element portions being secured with respect to each other and beingsecured to said anchor elements, said outer shell having a tooth-likeouter configuration and being received and secured on said base element.8. A method of securing and forming a dental prosthesis in a gap betweenspaced first and second teeth in the mouth of a patient comprising:a.securing first and second anchor elements to said first and secondteeth, respectively, in said gap; b. assembling a base element in saidgap, said base element comprising first and second base element portionswhich are receivable and securable in interfitting relation with saidfirst and second anchor elements, respectively, so that they arenonrotatable relative to said anchor elements, respectively, about anaxis which extends in a direction between said first and second anchorelements and which are received in interfitting relation and rotatablewith respect to each other and slidable in telescoping relation withrespect to each other in said direction to enable said base element tobe adjusted to fit the width of said gap; c. securing said first andsecond base element portions in fixed relation with respect to eachother; d. forming an outer shell having a tooth-like outer configurationon said base element; and e. securing said base element with said outercasing thereon to said anchor elements.
 9. In the method of claim 8 saidbase structure further comprising means biasing said first and secondbase element portions apart.
 10. In the method of claim 9 said anchorelements being tapered in their outward extents away from the gum ofsaid patient, said first and second base element portions beingconfigured to receive said first and second anchor elements,respectively, in snug interfitting relation when said base element isaligned with said gap and advanced toward said gum, said assembling stepbeing carried out by aligning said base element with said gap andadvancing it toward said gum so that said anchor elements are receivedin snug interfitting relation with said base element. .Iadd.
 11. In abase structure for a dental prosthesis wherein the base structure is ofa type which is permanently securable in a gap between spaced first andsecond teeth in the mouth of a patient and comprises a base elementreceivable in said gap and first and second securing means for securingsaid base element to said first and second teeth, respectively, toretain said base element in a position wherein it extends therebetween,the improvement comprising said base element comprising first and secondbase element portions which are securable to said first and secondteeth, respectively, with said first and second securing means,respectively, so that they are mountable relative to said first andsecond teeth, respectively, about an axis which extends in a directionbetween said first and second teeth, said first and second base elementportions being received in interfitting relation and being slidable intelescoping relation with respect to each other in said direction toenable said base element to be adjusted to fit the width of said gap,said first and second base element portions also being rotatable withrespect to each other about said axis to compensate for misalignment ofsaid first and second securing means. .Iaddend. .Iadd.12. The basestructure of claim 11 further comprising means biasing said base elementportions apart. .Iaddend. .Iadd.13. In the base structure of claim 11,said first base element portion having an aperture therein which extendsin said direction between said teeth, said second base element portioncomprising a pin which is slidably received in said aperture to enablesaid base element to be adjusted. .Iaddend. .Iadd.14. The base structureof claim 13 further comprising biasing means received in said apertureand engaging said pin to bias said first and second base elementportions apart. .Iaddend. .Iadd.15. In the base structure of claim 11,said first and second base element portions defining a tooth-likeconfiguration of reduced dimension in said base element. .Iaddend..Iadd.16. The base structure of claim 11 in combination with an outershell, said first and second base element portions being secured to eachother, said outer shell having a tooth-like configuration and beingreceived and secured on said base element..Iaddend.